Technical Abstract:
Dough rheological characteristics, such as resistance-to-extension and extensibility, are very important wheat flour quality traits evaluated in wheat-based food industries and wheat breeding programs. However, small sample size, rapid testing time, and large sample throughput are necessary in breeding programs, and are formidable challenges when using the standard Alveograph method (AACC method 54-30A). Therefore, a modified Alveograph test method was developed to measure dough extension characteristics that utilized 80 g flour at 60% water absorption and 2.5% salt solution. The dough was mixed for 4 min in a 100-g micro-mixer and then sheeted under a sheet roll (National Manufacturing Division, TMCO, Lincoln, NE). Three dough patties were prepared under controlled conditions and tested on the Alveograph.
Test results from this method modification showed that the flour sample size could be reduced 68% compared to the standard method, while simultaneously reducing analysis time by one third as well as making dough preparation more convenient in terms of dough mixing, dough forming, and cleaning. Data generated by this modified Alveograph method was significantly correlated with data generated by the standard Alveograph method. The correlation coefficients (r) for each of six Alveograph dough characteristics for 40 advanced breeding lines and wheat varieties grown in Texas, Oklahoma, Kansas, Colorado, Nebraska, and South Dakota were 0.92 for P (tenacity, maximum pressure required to reshape the sample), 0.73 for L (extensibility, curve length), 0.83 for W (dough strength, area under the curve), 0.90 for P/L (curve configuration ratio), 0.90 for le (elasticity, P200/P, P200: pressure 4 cm from the start of the curve), and 0.76 for G (swelling index, square root of the volume of air needed to rupture the bubble). Therefore, this modified Alveograph method could be very useful for wheat breeding programs, and could also be used as a viable alternative for milling and baking industries as well as wheat research.